72 UKN.SITIES OF OXYCEN AXU UYUKOCEN 



connection with the punii) had been chwetl. The fusible metal plug g \V!is now re- 

 moved, and the palladium was heated. 



AVhen the delivery of gas ceased, (/, Fig. 23, was closed by fusion. As 

 the palladium cooled off, most of the hydrogen remaining l)etweeu y and o. Fig. 

 27, was absorbed. If the vacuum <>l»taincd originally in this space was eipial 

 to the vacuum produced bv this re-absorption, tlii> l)laiik ^p.-ic- had absolutely 

 no effect on the e.xperiment. When the palladium w.-is cold, the tube was 

 closed by fusion at y. Fig. 25, / was separated fi-om the joint I, Fig. 26, and 

 cleaned, and the whole was made reaily foi" weighing. 



20. ]lYl)l{0(iEN UV NEW JLE-rilOD. MEASUUEMENT OF PKE.SSF1JE. 



When d, Fig. 23, had been closed by fusion, the pressure of the gas in the 

 globes was determined by observations of the syphou barometer, just as in series 

 second. Ice was heaped around the connecting tubes as shown above e, and the 

 ice around the globes was renewed. Then i-eadings were taken, as has already been 

 sufficiently described. 



The readings were continued at intervals for one hour; sometimes, in te.st 

 cases, for a day, but there never .seems to have been reason for sus})ecting the 

 accuracy of a reading taken after fifteen minutes from the end of the filling, 

 when the ice had been renewed an hour previously. 



21. lIVDIIotiKN 15V NEW MKTMOK. SE("OM> WKIiiUlNWi OF TU K I'A I.I.AIUUM. 



The tube containing the palladium now consisted of three parts: the large 

 part, closed again by fusion, the short tube containing the asbestos, and the point 

 whirh h.id been broken off at h, Fig. 2(1. The small parts were commonly united 

 l)y fusion. The laige part again presented a continuous suiface of glass ; its volume 

 was determined Ijy hydrostatic weighing. The volume of the smaller parts was 

 computed fiom their weight and specific gravity. In some earlier e.vperiments ft>r 

 a different purpose, the volume of the palladium tube was changed a little by the 

 heat which expelled the gas; but this did not occur in any experiment of this 

 series. If any change had occurred, the second hydrostatic \veighing \vould have 

 shown its amount. 



The tube w.is now weighe(l against the same counterpoi.se as before, with (he 

 exception that I lie ll.isks for e(]ualizing voluuies were not the same as before. A 

 larger volume of weights was now reipiireiband the palladium tube \vas smaller by 

 the capacity of the part between ij and /•, Fig. 2;"), which was closed when first 

 weighed, but w.ns now open to the air. These effects nearly counterbalanced 

 each other. 



